


Love Is Reverse Drowning

by DarkHeartInTheSky



Category: Supernatural
Genre: Animal Transformation, Fluff, M/M, Supportive Sam, Witch Curses
Language: English
Status: Completed
Published: 2018-01-13
Updated: 2018-01-13
Packaged: 2019-03-04 11:55:33
Rating: Not Rated
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,246
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13364187
Author URL: https://archiveofourown.org/users/DarkHeartInTheSky/pseuds/DarkHeartInTheSky
Summary: For the Dean/Cas Secret Santa Exchange.On a routine hunt, Cas is turned into a merman. Dean deals. Sam needs therapy. Everyone gets their happy ending.





	Love Is Reverse Drowning

**Author's Note:**

  * For [hit_the_books](https://archiveofourown.org/users/hit_the_books/gifts).



> Prompt: Castiel is turned into a merman while on a case and Dean goes into complete panic mode. Sam researches a cure, while Dean tries to help Castiel with his (hopefully - it's up to you) temporary circumstances. But as Dean cares for Castiel, he finds it really difficult to hold back the feelings he's been having for Castiel for a very long time. Meanwhile, Castiel is finding it a lot easier to express himself in his merman state.

                “Have I mentioned recently that I hate my life?”

                “Only about five minutes ago, Dean,” Sam said, shoving supplies into his duffel bag.

                “What about that I really hate witches?”

                “Only about eight times in the last hour.” Sam slung the duffel bag over his shoulder and picked up a large tome, tucking it under his arm.

                “What about—”

                “Whatever it is, yes, you’ve mentioned it recently. Probably very recently. Just shut up and—and watch him.”

                “Watch him?” Dean turned to the bath tub, then back to Sam. “He can’t go anywhere!”

                Behind him, the water sloshed rhythmically.

                “Just make sure he doesn’t—suffocate, or reverse drown, or something.”

                “Reverse drown? That really the best you can come up, college boy?”

                Sam glared, teeth gnashed together. “Shut the hell up and watch him! I’m going to find the witch and I will force her to undo the spell, but until then, you are going to sit your ass here, and keep an eye on him.”

                Dean opened his mouth to argue, then dutifully shut it. He sighed then looked back at Cas. Cas’s head and upper body were under the water, and the tail was parallel to the shower wall, fins tapping against the shower head.

                “He has _gills_ , Sam,” Dean said. He could see the organs right on Cas’s neck flexing every few seconds.

                “It’ll be fine,” Sam said. “I’ll fix this. I promise.”

                Dean swallowed. “I know.” He looked back at the tail, a bright-blue appendage that looked like it had the strength to break bones, if so inclined. “Keep me posted.” He thought for a moment. “And whatever you do, do not tell those British asshats what’s going on. They don’t need to know jack about this.”

                Sam huffed. “Wouldn’t dream of telling those guys anything. Don’t worry. I won’t take long.”  And then he was gone, out the door, and Dean was in the cramped motel bathroom, sitting on the edge of a cheap, fiberglass tub, staring at his best friend that somehow transformed species again.

                The witch had struck Cas out of nowhere. One second, Cas was watching Dean’s six, tall and strong as always, the next he was on the ground, flailing, minus legs, gasping for air.

                Dean had panicked. If it hadn’t been for Sam’s quick thinking, Cas might’ve died right there. But Sam was always the level headed one. The one that could think straight in a crisis. The Impala thankfully was only outside the building they had been investigating. Sam raced to it, but only after giving Dean the water bottles in his backpack. Dean had spent long minutes carefully and frugally spilling water over the gills, and then when Sam did come with the Impala, Dean sat in the backseat and continued the routine, until they got to the motel and Sam filled the tub with just enough water that they could make Cas over.

                The water was to the brim now, and every now and then a little bit would splash out when Cas moved.

                “At least you’re having fun,” Dean grumbled, resting his chin on his fist. Cas’s eyes moved wildly under the water, and every now and then, he’d grin sheepishly. He hadn’t said a word since the spell struck him.

                The tail slapped the tile wall hard and a bit of water fell from the showerhead onto Dean.

                “Hey!” he screeched. “Goddamnit, that’s cold. Knock it off, would ya?”

                Cas kept smiling.

                Dean huffed. “ _Now_ you smile. What, it take almost reverse drowning to knock a sense of humor into you?”

                Cas sat up suddenly, his hair sticking to his face. He looked at Dean. His eyes seemed bluer than normal, water droplets clinging to his eyelashes. He leaned forward and pressed his nose to Dean’s neck. Dean jerked back.

                “What the hell, man?”

                Cas sniffed him, like a dog did a stranger. Dean jerked back again and stood.

                “Personal. Space.”

                Cas still stared and smiled, the tail swinging back and forth.

                Dean swallowed and turned around, pinching the bridge of his nose. He tried to quell his anxiety, and all the other feelings swirling around through his head. But when he closed his eyes, he was back in the Impala, Cas squirming in his lap, choking on air—Dean, trying his best to pour just enough water over the gills to last another few seconds before he’d do it again. He thought for the entirety of that horrible, endless drive Cas was going to die right there, in his lap, and there was nothing he could do about it.

                Cas survived Lucifer. He survived Amara doing—whatever it was she did to him. He couldn’t die by the hands of Sabrina the teenage witch.

                Cas kept looking at him. Dean felt the stare burning into his back. A blush crept up the nape of Dean’s neck. He scratched it awkwardly and cleared his throat. It was bad enough being with Sam when Cas did the staring thing. But when they were alone, it was somehow even worse. Cas looked at Dean like he could see right through. Straight to the soul.

                And Cas did know Dean’s soul. He held Dean’s soul once. Cradled it against himself. When Dean was alone with Cas, he had no secrets. Cas knew Dean better than even Sam did.

                And that was terrifying.

                Cas knew everything Dean did; in Hell and back up top. And he still looked at Dean like _that_ , like Dean was worth more than the Earth and stars and moon and sun.

                That was even more terrifying.

                Dean shook his hands, tried to get his bearings before he turned back around. Cas was underwater again, the tail hanging over the tub now.

                Dean walked back to the tub and looked at Cas. Cas smiled. Dean couldn’t help but smile again. He leaned against the corner where the tub met the other wall.

                “At least you’re alive, eh?”

                It occurred to Dean suddenly. If somehow Sam didn’t find the witch, or if killing her didn’t reverse the spell, and Cas was stuck like this. . . they’d make it work. Somehow. Someway. They’d figure it out, like they figured everything out. Something better than this. Cas couldn’t spend the rest of his life in a bathtub. Sam probably could configure something better.

                He’d take Cas in any shape, form, species—as long as he was alive.

                “The not talking thing’s gonna suck, though,” Dean sighed. He sat down on the toilet. Still, even if Cas couldn’t talk, he was communicating with body language and facial expressions. It was strange. Dean had never seen Cas smile this much in all the time they’d known each other.

                Dean looked back at the tail. It was long and muscular—he could see veins bulging underneath the scales.

                “Traded wings for that thing, huh? I think I’d ask for a refund if I were you.”  
               

Cas froze. He frowned, and for the first time since the nightmare started, the tail stopped moving.

                “Cas?”

                Cas slid back underneath the water, slowly. There was a weight to his shoulders, and that ever present frown was back.

                “Ah, come on man. I—I didn’t mean anything by it. It was a stupid joke. A really stupid joke. I’m a dick, you know that.”

                Cas’s tail fins flipped sadly. Dean wasn’t sure how it was possible, but there was no other way to describe it.

                Dean sighed. He really screwed it up this time. Cas couldn’t fly anymore—and Dean had just reminded him of it. Dean sat back down on the tub edge. He rubbed his face.

                “Water warm enough?” Dean idly ran his fingertips over the surface. It was room temperature. “I need to add more hot?” What the hell kind of water did Cas even need? Hot? Cold?

                Cas shook his head.

                “Cas, I’m sorry.”

                Cas nodded. The tail pressed up against Dean’s thigh. Dean huffed and patted it. It was smooth. Not at all like Dean imagined it would feel. He could see the scales, layered on top of one another, but they weren’t sharp, or jagged. It was like soft skin.

                Cas flicked his tail fins again and smiled shyly. The blush crept back up Dean’s face.

                “Uh,” he said, clearing his throat. “Look, man, I gotta pee. Turn around.”

                Cas sighed, shrugged his shoulders. He turned around as much as he could in the small tub, facing away from Dean. Dean could hear the eye roll. He imagined what Cas was saying—probably something along the lines of, _humans, so strange with all the modesty._

                Dean finished his business quick.

                He had spent the better part of last year fighting to free Cas from Lucifer. And while they had won that battle, barely, everything Dean imagined doing, he hadn’t. Freeing Cas was supposed to lead to something _more_. But then Mom came back, and the British Dicks shoved their noses into places they didn’t belong, and things just got way more complicated than they ever had before.

                Everything he had imagined crumbled.

                And he almost lost Cas, again. There was that horrible second when he first saw Cas, on the ground, clothes beside him, before his brain fully comprehended what had happened, he thought Cas was dead.

                How many second chances would they get? How many times would they get so close, inches apart, only to be torn away from one another?

                He couldn’t help but think of that Ishim dick. How he talked to Cas. Looked at Cas like he was scum beneath his boots. It reminded Dean of what Cas used to be. Respected; a leader of a heavenly garrison of angels. Cas had been the one to lead the siege down into Hell in the first place. Cas was ancient. As old as the stars.

                Sometimes, when they were having move nights, or pizza parties, or playing drunk Apples to Apples, Dean forgot about all that. Then, Cas was just a guy. His best friend.

                But Cas would always be more than that. Always would be in the odd space Dean couldn’t ever define. All he really knew for sure was that when Cas wasn’t around, there was an empty space in Dean’s heart that couldn’t be filled until Cas came back. Last year had been one of the worst years of his life. Probably worse than the countdown year of his demon deal. Cas had been out there, Lucifer riding his skin, and Dean didn’t know how to save him, and worse, why Cas had done it in the first place.

                _Your human weakness._

                That’s what Ishim called him. Cas’s human weakness. And it was true. Dean made Cas weaker. He used to think that Cas being more human was a good thing. He wanted to think that. But sometimes, it was hard to maintain that belief. Especially when it came to other angels. Cas’s old buddies, and how they treated him now.

                Cas splashed his tail again. He was sitting up once more, scowling. Somehow, Dean knew what Cas was thinking.

                _You think too much_ , his eyes said.

                Dean scoffed. “Yeah, well, some of us don’t seem to think at all. You know I’m never letting you live this down, right? Seriously—a witch? Rowena, I get. I’ve seen her work, she’s powerful. But c’mon, man. This chick is like, a book one Harry Potter. At best.”

                Cas smiled again. It lit up his eyes. He leaned over the edge of the tub.

                “Hey, watch it, now. No falling over.”

                Cas kept leaning, hands braced against the tub edge, tail awkwardly curled towards the toilet. He was a breath away from Dean. Dean saw all the different shades of blue in his eyes; the sparkles, the way the light refracted off them. They were shining with something familiar—that same adoration only he ever seemed to get from Cas. Not even Sam got those looks, those special smiles. It didn’t help Dean at all—the blush ran up his neck faster, hotter. He couldn’t move though. Cas’s gaze was magnetic. He didn’t know how long they stayed like that, just staring one another. It happened whenever they had these little staring contests—Sam called in eye fucking, jokingly, with an eyeroll—but Dean didn’t like that. Eye fucking felt dirty, and this wasn’t dirty. These gazes with Castiel were probably the purest thing Dean ever had.

                Dean swallowed. Cas finally broke eye contact, eyes looking down at Dean’s lips. And then, Cas was leaning ever forward, water moving, dripping down his skin. He pressed his lips against Dean’s. They were strangely soft, and tasted like saltwater. Dean was frozen at first, a million incoherent half-thoughts racing through his mind; but it only lasted a second, and then he relaxed, muscles unclenching, and he returned the kiss. He opened his mouth slightly, curling his lips around Cas’s.

                He had imagined this. A few times, here and there, throughout the years. With the way Cas looked at him, Dean didn’t think it’d be possible not to. And of course, there’d be his own shit; feelings for Cas he couldn’t ever fully explain. All he knew for sure was that Cas filled a part of his soul not even Sam could manage. He wasn’t complete unless he had Sam and Cas.

                And Cas was so sweet, gentle, all intimacy and soul. It was sweet.

                They finally broke and then Cas pressed his forehead against Dean’s, traced his thumb up and down Dean’s jawline.

                “Cas?”

                Cas hummed, tailfins flipping back and forth idly.

                .

                .

                .

                Dean braced his back against the tub. Cas leaned over the edge. Every so often, he’d dip his face back under water for a few seconds, then he’d be back right there, next to Dean.

                “I’m starting to worry about Sam.” It’d be hours since Sam left, and Dean hadn’t heard a peep. He looked to Cas. “If Sabrina had the juice to mojo you, what the hell can she do to Sam?”

                Cas twirled his fingers around Dean’s hair.

                “The hell is up with you, man?” Dean scoffed. “You can’t even return a hug, normally. Is it the fish hormones?”

                Cas smacked Dean upside the head.

                “Ow!”

                Cas glared, but inly for a second. Then he was smiling again—that smile that was so rare, and damnit. Dean melted. He sighed and patted Cas’s cheek, relaxing marginally.

                It happened suddenly again. Dean zoned out for a bit, relaxed beside Cas’s soft ministrations, thinking still about their kiss—wondering what this meant. If there’d be more kisses in the future.

                Cas woke Dean. Lukewarm water was going everywhere.

                “Cas, the hell?” Dean snapped, but the words were sucked out of his throat when he noticed the tail and gills were gone. “Cas?”

                Cas looked around sheepishly. He swallowed. “Hello, Dean,” he said slowly. His voice was hoarse.

                Dean balked for a moment. “You—you’re okay?” Dean peered over, trying not to see too much of anything. He caught a glimpse of toes. “Back to normal?”

                Cas wiggled his toes. “I think so.” Cas frowned, thinking. Then he looked at Dean. “Dean. I’m naked.”

                Dean couldn’t help it. He burst out laughing. Relief, euphoria, it all washed over him and he laughed until he couldn’t breathe.

                “Good to have you back, Cas.”

.

.

.

                Sam came back a few hours later. Dirt was smeared over his face, his hair was caked in mud, and he looked pissed off, but otherwise, unhurt. Dean and Cas were on the bed, watching soap operas on the crappy motel TV. Cas wore a pair of Dean’s pajamas pants and an old band tee shirt, the logo so faded, the band name couldn’t even be made out.

                “That was an adventure,” Sam snapped as he entered, tossing his bag carelessly to the ground. “She pushed me in the mud.”

                “Looks good on you,” Dean said, winking. “Really brings out your pores.”

                “Shut up.” Then he finally noticed Cas sitting beside Dean. “Cas, you feeling okay?”

                “Yes.” Cas lifted up one leg. “Thank you, Sam.”

                “Yeah, of course,” Sam said. Then he narrowed his eyes, and stared at Dean studiously. It was unnerving. Dean fidgeted, tried not to stare back, tried to just watch the lame TV show, but it grew harder and harder by the second. Finally, Sam broke. “Dean, can I talk to you outside for a minute?”

                Dean slowly slide off the bed, throat tight. “We’ll just be right outside,” Dean said, but Cas seemed to be mesmerized by the show. It was cold outside. Sam shut the door.

                “What happened while I was gone?”

                “Nothing,” Dean said. “One second he’s got a tail, the next, it’s gone. Figured it happened when you popped the witch.”

                “I didn’t kill her,” Sam said.

                “What? You let her go?”

                “I made her undo the spell. She swore off magic forever. Said this was all a prank that just way out of hand.”

                “And you believed her?”

                “I told her if she got back into magic, then I would hunt her down and kill her. But that’s not the point—she told me the spell she put on Cas was something she was trying. A combination of two spells.”

                “What two spells,” Dean asked slowly.

                “A transformation spell, and a truth spell. But wires got crossed or something, because the transformation spell made it so he couldn’t speak, but the truth spell was still pulling at him, so I’m going to ask you again: what happened while I was gone?”

                Sam still stared at him, lawyer eyes and all.

                And Dean couldn’t handle Sam being mad at him under any circumstance. He told everything.

                There wasn’t much to tell, really. It was just a kiss. But to Dean, it was so much more than that. And suddenly, it occurred to Dean, that Sam’s reaction was very, very, very important.

                When Dean finished, Sam relaxed, sighing. The tension fell out of his shoulders. Then he smiled. And chuckled.

                “Well,” Sam said. “Not how I imagined it going, but I guess beggars can’t be choosers.”

                Dean balked at Sam. “What?”

                “You think I didn’t know?”

                Dean tried to snap, but he couldn’t find the words. He gaped at Sam like an idiotic fish. Sam huffed.

                “If you saw the way you two looked at each other, you’d understand.”

                “That obvious?”

                “That obvious,” Sam said, mouth pressed in a thin line. He slapped Dean on the shoulder. “I’m happy for you guys. Seriously. Been waiting for this for years.”

                “If you knew, why didn’t you ever say anything?”

                “Not my place. Anyway, c’mon. We’ll head back home tomorrow. I’m beat. And I need a shower.”

                Sam went back inside the room. Dean stood flabbergasted for a moment before he followed. His brain lagged behind his body. Before he knew it, he was back on the bed beside Cas. His arm went over Cas’s neck, and then Cas was leaning his head against Dean’s shoulder.

                Sam kept smiling as he gathered his toiletries to take into the bathroom.

                “What’re you looking at, bitch?” Dean said, but there was no heat behind it.

                “Have fun you two,” Sam said, and then he closed the bathroom door.

                Dean and Cas watched the movie. And for the first time in a long time, Dean was happy. Not content, but truly happy.

                For the first time in a long time, Dean looked forward to what the future might bring.

**Author's Note:**

> Dear hit_the_books 
> 
> thank you for the opportunity to write something I normally wouldn't have ever attempted.


End file.
